Integrated Pest Management of Corn

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Transcript of Integrated Pest Management of Corn

Pest and Diseases of CornINSECT PEST IN CORNCorn BorerCommon Name: Asiatic Corn BorerScientific Name: Ostrinia furnacalis (Guenee)Local Name: Dalipog (Ilocano); Amasok or Tibgoy (Bicol/Ilonggo)Tuhob (Cebuano)DescriptionEggs are flat, creamy, shiny and laid in mass (about 25-50 eggs/egg mass) in fish scale-like arrangement on both sides of the corn leaves. Incubation Period is 4-5 days.Newly hatched larvae are pinkish with black or brown heads. Later instars are creamy creamy and brownish-yellow. It molts five times from 12-13 days.The pupa is dark red and the pupal period is about 5-12 days.Total development period from egg to adult emergence ranges from 27-52 days.DamagePinhole lines lesions on the leaves caused by first instar larvae.Match head-size holes and elonated lesions on leaves and leaf sheaths caused by second and third instar larvae.Broken stalks and leaves.Premature drying of whole plant and ear.Control MeasureEarly and synchronous planting in contiguous areas using resistant varieties.Manual picking/crushing of eggs or egg masses and larvae while inspecting the plants.Detasseling of clumped tassels one to two days after emergence or detasseling three rows out of four rows of corn plants.Trichogamma parasites at 33-35 days after planting (after hilling-up) at 3-4 days intervals.Crop rotation coupled with weeds elimination.CORN DISEASESBIOLOGICAL CONTROLINTEGRATED PEST MANAGEMENT ON CORNIntroCorn Seedling MaggotScientific name: Atherigona oriyzae (Malloch)Local names: Adult: Bangaw (Bicol): Ngilaw (Ilocano); Langaw (Ibanag)Larva: Apihis (Cebuano)DescriptionEggs are elongated, pearl-white turning dark when about to hatch, anterior and roundish, slightly curved and laid singly in the outer surface of the leaves.Incubation period is 2-3 days.Newly hatched larvae are creamy white to transparent, elongated and taper towards the head end, becoming dark yellow in the last instar. Larvae undergo three instars from 8-18 days.The pupa is ovoid and light to dark brown. Pupal period is 5-11 days.The adults are greenish-black with three blackish stripes on the back of the thorax and three pairs of black spots on the last abdominal segments.DamageLeaf feeding lesions, curling and breaking of young leaves.Wilting, drying and rotting of central shoot.Infested seedlings show stunted growth and later may produce side tillers.Control measureSynchronous planting in contiguous areas.Early planting in the growing season to escape high maggot population.Clean culture including the removal of alternate host plants.Seed treatment with thiodicarb or carbofuran ST before planting.Integrated pest management (IPM), also known as Integrated Pest Control (IPC) is a broad-based approach that integrates practices for economic control of pests.History of cornat least 7000 years ago - Scientists believe people living in central Mexico developed corn.

1492 -when Columbus's men discovered this new grain in Cuba. It was exported to Europe rather than being imported, as were other major grains.

1575 - it was making its way into western China, and had become important in the Philippines and the East Indies.Pest of corn*corn rust*corn seedling maggot*white grub*common cutworm*corn ear worm*corn thripsDiseases of Corn*DOWNY MILDEW*CORN RUST*CORN SMUTCommon CutwormScientific name: Spodoptera lituraLocal names: Ulod (Ilong0,Bicol); Arabas (Ilocano)DescriptionEggs are round pale white and laid in mass on leaves or objects on the ground covered with yellowish-brown hairs. Incubation period is 3-5 days.Young larva is greenish with black band one-third of the length from head and a full-grown larva (developed from 20-30 days) is green with bright yellow dorsals line and lateral stripes with black spots.The pupa is reddish brown and about 1.6 cm long. the pupation period in soils is from 6-10 days.The adult is about 20-25 mm long with wings (forewings are purplish-brown with numerous lines and spots and hind wings are whitish with narrow band along the center margins).DamageScrapping of leaf tissues by young larvae, leaving irregular grayish white patterns on the leaves.Older larvae may cut stems and leaves, including veins and midribs.Young plants may be completely defoliated by older larvae (third to sixth instarsa).Control measurePlow fields to remove weeds which may serve as alternate hosts.Collect egg masses and crush themMake small trenches around the field and put some cut grasses for shade. Collect hiding larvae during early morning.Chemical spraying if severe infestation (use pyrethroids).Corn EarwormScientific name: Helicoverpa armigera (Huber)Local name: Ulod na puso (Cebuano)DescriptionEggs are sub spherical and laid singly on corn silk. Newly laid eggs are cream then turn dark when about to hatch. Incubation ranges from 2-5 days.Newly hatched larva has pale yellowish-white with black head and walks with looping motion. Older larva turns plae green to dark brown. It molts six times within 12-24 days.Pupa is yellowish-green when newly pupated turning dark brown as it matures. Pupation usually takes place in the soil from 34-45 days.The adult is brown with dark waxy lines across the wings. Forewings of the male corn earworm have dark centered circular spot on the middle.DamageRow of shotholes on unfolding leaves, caused by the first to second instar larvae at whorl stage.Irregular elongated holes on the leaves caused by third to sixth instar larvae.Cutting of silk and feeding into the tip of developing ear and kernels.Feeding on emerging tassles.Control measurePlant resistant varieties with long and tight ear husks.Plant marigold aroun the field as trap crop.Corn PlanthopperScientific name: Peregrinus maidis (Ashmed)DescriptionEggs are small white and flask-shaped and laid in mass in longitudinal slits on the upper surface of the leaves, usually near the stalk.The nymph is yellowish and somewhat mottled black and wingless.The adult is soft pale yellowish after emergence. Its wings are whitish and devoid.DamageSucking of plant juice from young leaves and leaf sheath causing loss of plant vigor.May transmit the maize stripe or maize mosaic virus.Toxin from the insect may cause galls along the vains of underneath leaf surface and stunted plant growth.Control measurePlant resistant varietiesEliminate weedsCorn ThripScientific name: Frankliniella williamsi (Hood)DescriptionEggs are bean-shaped and translucent white. They appear as very tiny circular, shiny spot on the leaf if held against the sun and laid singly inside the upper tissue of the leaf blade. Incubation period is 3-4 days.Full-grown larva is transparent white and about 1.3 mm long. Larval period is 5-8 days. Destructive stage.The pupa is whitish yellow, has shorter body with white transparent wing pads. Pupation takes place in the soil and lasts foe 2-3 days.The adult is light brown and about 1.4-1.74 mm long. Destruxtive stage.DamageLarvae and adult suck plant sap from young leaves causing mottled discoloration.Young plant growth is retrded when severe infestation occurs.Control measureSynchronous plantingClean culture including the removal of alternate hosts such as grass species.Some Common Parasites and their PredatorParasitesPredatorSpiders-adult semilooper, cutworm, army worm and other adult insect pestDragonfly-adult semilooper, cutworm, army worm, and other adult insect pestLady Beetle-aphids, corn borer eggmassAnts-egg/larvae of insect pestEarwings- larvae and pupae of insectpestLonghorne Grasshopper-eggs of insect pest and nymphs of plant hoppersLacewing-aphids amd leafydopterous pestCotesia/Apantales- larva semilooperTrichogamma- corn borereggmass, earworm eggWasp- semilooper larvae, caterpillarDowny MildewScientific name: Pernosclerospora philippinensis

(Weton Shaw)Type: FungusPlant growth satges affected: Two leaf stage to Silking StageSymptomsWhite yellow streaks first st the base then on entire leaf blade.White growth on both sides of the streak when humidity is high (e.g., during the night when there is dew formation or when leaves are wet due to rain).Dwarfing when reduced elongation of the internodes.Ears and tassels poorly formed if severely infected.Presence of spores in the lower portion of leaves.Control measureCultural methodPlant resistant varietiesSynchronous plantingImmediately rogue infected plantEliminate weed hostBurn infected plantChemicalSeed treatment using fungicidesLeaf RustScientific name: Puccinia polysoraType: FungusPlant growth stages affected: Mid-whorl to silking stageSymptomsPresence of small and circular brown rusty pustules or blisters on upper and lower ssurface leaves.Blisters are rough, may later break and release numerous rusty spores.Control measurePlant resistant varietiesCorn SmutScientific name: Ustillago mayidsType: FungusDisease development is favored by high nitrogen level or high quantities of manure. Injuries may be brought about by blowing soil or sand particles, cultivation, spraying or detasseling.SymptomsGalls of boils on above ground tissues.Galls first appear as glistening white or grayish white swellings.Interior of galls later becomes black and powdery that contains numerous sooty masses of spores.Control measureMaintain a well balanced soil fertility based on soil test.Practice crop rotation.Avoid mechanical injury to plants during cultivation.In small scale, remove and destroy galls before they rupture and release spores.Plant resistant varieties.